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Clinical Parasitology > Amoeba Part 1 > Flashcards

Amoeba Part 1 Flashcards

1
Q

nn

Medically important Parasites

There are 6 Phylum

A

Phylum Sarcomastigohpora
Phylum Ciliophora (Ciliates)
Phylum Apicomplexa
Phylum Microsporidia
Phylum Aschelminthes (Class nematodes)
Phylum Platylhelminthes (Flatworms)

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2
Q

Under the Phylum Sarcomastigophora

There are 2 Subphylum

A

Subphylum Sarcodina (Ameba)
Subphylum Mastigophora (Flagellates)

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3
Q

What phylum is this?

It has a suborder of Haemosprina
Parasites that are not equipped with de

A

Phylum Apicomplexa

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4
Q

What phylum is this?

Are intracellular parasites
Now classified as fungi
They are *spore

Has unique feature of Polar tube

A

Phylum Microsporidia

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5
Q

They are single-celled, eukaryotic organisms

meaning you can expect to find a nucleus and organells in their cytoplas

A

Protozoans (Kingdom Protista)

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6
Q

Characteristics of Protozoans

Own words

A
  • Unicellular organisms
  • vary in shape, size, locomotion
  • reproduce either asexually (by binary fission) or sexually (sporogony or gametogony)
  • do not possess a cell wall
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7
Q

The cytoplasms of protozoans have 2 regions.

What are those?

A

Endoplasm
Ectoplasm

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8
Q

Outer region also called gel

for protection; more clear and more hyaline than endoplasm

A

Ectoplasm

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9
Q

It is also known as Ameba

protozoans that possess pseudopod or pseudopodia for locomotion

A

Sarcodina

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9
Q

Inner region also called sol region

primary function is nutriyion and metabolic processes

A

Endoplasm

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10
Q

Also called false feet

3which are foot-like processes which would funcyion for locomotion

A

Pseudopodia

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11
Q

Sarcodina (Ameba)
inhabit the large intestine except what?

A

E. gingivalis

since it is found in the mouth/or the oral cavity

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12
Q
A
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13
Q

Entamoeba possess what chromatin?

which is located on the edge of the nucleus

A

Peripheral chromatin

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14
Q

The nucleus in the group entamoeba is what?

has spaces or holes

A

Vesicular

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15
Q

All are commensals except what?

Commensals means they are non-pathogenic

A

E. histolytica

it is the only pathogenic member of Amoeba

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16
Q

There are 2 stages of development of Protozoans

A

Trophozoites
Cyst

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17
Q

Type of Stages of development of Protozoans

in most cases, it is the IS (infective stage). Wherein the ingestion of the parasite will lead to an infection

* Resistant stage
* Non-motile
* found in either formed or watery stool

A

Cyst

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18
Q

Type of Stages of development of Protozoans

Vegetative stage of Amoeba and other Protozoans

* Feeding stage
* Can be recovered in stool
* recovered in watery or di

A

Trophozoites

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19
Q

What parasite is this?

The only pathogenic member of Amoeba

A

Entamoeba histolytica

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20
Q

Mode of transmission

Entamoeba histolytica

A

Ingestion of Inefective Cyst

In this parasite, mature form, the infective cyst is described to be qua

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21
Q

Habitat

Entamoeba histolytica

A

Large Intestine

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22
Q

Final Host

Entamoeba histolytica

A

Man

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23
Q

own words

Life Cycle

Entamoeba histolytica

A
  1. Ingestion of cyst
  2. Excystationin the small intestine (cyst to torph)
  3. Become a Metacyst
  4. Turns into a Amoebulae/Metacystic Trophozoite
  5. Production of Trophozoite in colon (thru asexual repro)
  6. There will be Encystationin large intestine (troph to cyst)
  7. Produced cyst is called precyst
  8. Released to stool
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24
Q

It is the most common site of extra-intestinal amoebiasis/infections

A

Liver

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25
Q

Cyst Morphology

Entamoeba histolytica

A

Cyst would have up tp 4 nuclei

(There is dark structure which is the karyosome composed of RNA and is centrally located

+ Peripheral chromatic is on the edge of the nucleus

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26
Q

Cyst Morphology

Entamoeba histolytica

A

There is also Chromatoidal body or chromidial bar/body

Sausage-like structures that contains crystalline RNA

Function as energy source
Appear as cigar-shaped/sausage-shaped
There is also the presence of glycogen vacuoles

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27
Q

Trophozoite Morphology

Entamoeba histolytica

A

In direct mount, it is progressive and unidirectional. Has only 1 nucleus

Take note of the presence of pseudopodia

Trophozoite releases pseudopodia one at a time
Centrally located karyosome
Surrounded by fine and smooth peripheral chromatin
Has the appearance of the cytoplasm (clean-looking)
May contain ingested RBC

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28
Q

Disease Manifestation

Entamoeba histolytica

Asymptomatic Carrier State

A

Majority (90%) of cases areasymptomatic

29
Q

Disease Manifestation

Entamoeba histolytica

Intestinal Disease

A

Approx. 10% of infected patients would have symptoms

less than 1% would have extra-inestinal diseases

In intestinal disease, the incubation period is aroun
1-4 weeks

30
Q

Signs and Symptoms of Intestinal Disease

Entamoeba histolytica

A
  • Diarrhea
  • Amebic Dysentery (Bloody Diarrhea). The
    presence of blood in stool would indicate that
    the parasite is invasive because it’s
    destorying the lining of the intestine.
  • Abdominal Pain
  • Flatulence
  • Weight loss
  • Chronic Fatigue
  • Foul smell of stool
  • Blood and mucus in stool sample
31
Q

Disease Manifestation II

Entamoeba histolytica

Intestinal Disease

A
  • Release of Enzymes to lyse mucosal lining
  • Formation of Flask Shaped Ulcers

In a biopsy, because of the invasive property of the parasite, the parasite is capable of producing Flask shaped ulcer - something quite unique with Entamoeba Histolytica

32
Q

Disease Manifestation: Clinical forms of intestinal Amebiasis

Entamoeba histolytica

A
  • Dysentery
  • Fulminating Colitis, a severe form of diarrhea.This can be deadly because it may
    lead to perforation or destruction of the colon
  • Amebic Appendicitis
  • Ameboma - granulomas; an inflammatory response usually seen in chronic
    inflammation; may be mistaken as cancer
    (carcinoma)
33
Q

Disease Manifestation

Entamoeba histolytica

Extra-intestinal Disease

A
  • Around less than 1 percent (<1%) of infected patients have extra-intestinal disease
  • Ectopic form of amebiasis- It means that it usually occurs in the Liver that can lead to Amebic Liver Abscess
  • Signs of Ectopic: Fever, Right Upper Quadrant Pain, Tender Liver, Hepatomegaly
  • Cutaneous Amebiasis (Amebiasis cutis)- A complication of dysentery wherein there
    will be a painful ulceration near the
    anus/peri-anal area

The parasite can affect the liver, leading to amoebic
liver abscess. It can also affect the brain and lungs,
which also leads to abscess

34
Q

Pathology

Entamoeba histolytica

A
  • Has the ability to lyse tissues
  • Attributed to its virulence factors: Lectin, Amebapores, Presence of Cysteine Proteinases
35
Q

Pathology: Virulence Factors
which is responsible for the attachmen of the parasite

Entamoeba histolytica

A

Lectin (Gal/GalNAc Lectin)

36
Q

Pathology: Virulence Factors
which promotes formation of holes

Entamoeba histolytica

A

Amebapores

37
Q

Pathology: Virulence Factors
This are presence of ltic enzymed that will lead to tissue destruction. The reason for parasite to spread

A

Presence of Cysteine Proteinases

38
Q

What diagnosis is this?

  • different from bacterial dysentery
  • there is mucus and blood in stool
  • no granulocytosis (no high level of WBC)
  • no high fever
A

Amebiasis Differential Diagnosis

38
Q

Drainage of a liver abscess

Aspirated fluid from the liver looks like what?

where trophozoite can be seen

A

Anchovy Sauce

39
Q

Laboratory Diagnosis for amebiasis

Entamoeba histolytica

40
Q

Ova and Parasite Examination

Entamoeba histolytica

There are 3 Examination

A
  1. Direct Fecal Smear (DFS)
  2. Concentration Technique
  3. Permanent Stained Smear (Iron Hematoxylin or Trichrome Stain)
41
Q

General rule:

If you find cysts ortrophozoites in DFS and Conc. Techniques, is it conlusive or not?

A

No, it is not yet conclusive.

You have to do the third step in Ova and Parasite Examination-Permanent Stained smear

42
Q

Used for confirmation of the presence of intestinal protozoan. This step is required for confirming intestinal protozoan

What ova andparasite examination?

A

Permanent Stained smear

43
Q
  • It is where we are detecting Antigens
  • Immunoassays are done as well

Entamoeba histolytica

Note that specimen should be freshly passed stool

A

Serology (ELISA), IHA

44
Q

This is where flas-shaped ulcers can be seen

Entamoeba histolytica

A

Rectal Biopsy

45
Q

This is used especially in cases of amebic liver abscess

Entamoeba histolytica

A

Examination of Liver Aspirates

46
Q

Epidemiology

Entamoeba histolytica

A
  • Worldwide distribution
  • Practicing homosexuals (MSM)
  • Those with poor access to clean water
47
Q

Recent identification of a E. histolytica look-alike:

A
  • E. dispar
  • E. moshkovskii - formally known as Laredo strain
  • Entamoeba bangladesh
48
Q

What would be the manner of reporting if we see any cysts or cyst stages of entamoeba?

A

Entamoeba histolytica/dispar

49
Q

Treatment

Entamoeba histolytica

A
  • Metronidazole
  • Diloxanide Furoate (esp. forasymptomatic carriers
  • Iodoquinol
50
Q

Prevention

Entamoeba histolytica

A
  • Proper disposal of waste
  • Proper sanitation
  • Access to safe water & food
  • Development of an effective vaccine

Currently don’t have effective vaccine against amebiasis

51
Q

Other Commensal amebae

  • Generally do not cause disease
  • Non-pathogenic Ameba that you may encounter in the
    stool
  • The Common reason why this is present in stool is
    due to drinking fecally contaminated water
  • Have same or similar life cycle as E. histolytica
A
  1. E. coli
  2. E. hartmanni
  3. E. polecki
  4. E. chattoni
  5. E. nana
  6. Iodamoeba butschlii
  7. E. gingivalis
52
Q

It is very common commensal

53
Q

E. coli Cyst

in terms or Nuclei

A
  • will have up to 8 nuclei
54
Q

E. coli cyst

In terms of Karyosome

A

karyosome would be eccentric (not centrally located

55
Q

E. coli Cyst

In terms of Peripheral chromatin

A

Appear as “Coarse or rough’

56
Q

E. coli cyst

In terms of Chromatoidal bars

A

described as needlle-like, splintered, broomstickor witch broom

57
Q

E. coli trophozoite is bigger or smaller than E. histolytica?

A

bigger than E.histolytica

58
Q

E. coli trophozoite

In terms of movement and psedopodia

A

Movement: Sluggish; non-progressive
Pseudopodia: ‘blunt”

moving but it stays in the same place

59
Q

E. coli trophozoite

in terms of Pseudopodia

A

Described as “blunt”

60
Q

E. coli trophozoite

in terms of the nucleus, karyosome, and peripheral chromatin

A

1 nucleus, with eccentric karyosomeand rough/course peripheral chromatin

61
Q

E. coli trophozoite

In terms of cytoplasm

A

Dirty-looking appearance

would have ingested material like bacteria and fungi.

62
Q

Also known as “small race of E. histolytica”

because it is similar to E. histolytica but this parasite is smaller

Commensal

A

Entamoeba hartmanni

63
Q

E. hartmanni

In terms of movement

A

sluggish; non-progressive

64
Q
  • The ameba of pigs and monkeys
  • most common parasite in Papua new Guinea
  • Quite difficult to identify; may resemble other entamoeba species

  • The presence of chromatoidal bar is the most
    important feature of Entamoeba polecki
  • Presence of angular/pointed chromatoidal
    bar
  • Presence of only one nucleus (cyst/troph) and the karyosome is found in the center.
A

Entamoeba polecki

65
Q

E. polecki trophozoite

in terms of nucleus, movement, karyosome, peripheral chromatin

A

Nucleus: 1
Movement: progressive
Karyosome: at the center
PC: Evenly distributed

66
Q

What parasite?

Morphologically similar to E. polecki

Seen in apes and monkeys

A

Entamoeba Chattoni

67
Q

What parasite?

Smallest intestinal amebae (as small as RBC)

Commensal and is oval in shape

A

Endolimax nana

Clinical Parasitology (9 decks)

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